Kargacin G J
Department of Medical Physiology, University of Calgary, Canada.
Biophys J. 1994 Jul;67(1):262-72. doi: 10.1016/S0006-3495(94)80477-1.
One- and two-dimensional models of Ca2+ diffusion and regulation were developed and used to study the magnitudes and the spatial and temporal characteristics of the Ca2+ transients that are likely to develop in smooth muscle cells in restricted diffusion spaces between the plasma membrane and intracellular organelles. Simulations with the models showed that high [Ca2+] (on the order of several microM) can develop in such spaces and persist for 100-200 ms. These Ca2+ transients could: 1) facilitate the coupling of Ca2+ influx to intracellular Ca2+ release; 2) provide a mechanism for the regulation of stored Ca2+ that does not affect the contractile state of smooth muscle; 3) locally activate specific signal transduction pathways, before, or without activating other Ca2+ dependent pathways in the central cytoplasm of the cell. The latter possibility suggests that independent enzymatic processes in cells could be differentially regulated by the same intracellular second messenger.
建立了钙离子扩散和调节的一维和二维模型，并用于研究在质膜和细胞内细胞器之间受限扩散空间中平滑肌细胞可能出现的钙离子瞬变的大小以及时空特征。模型模拟表明，在此类空间中可产生高浓度的钙离子（几微摩尔量级）并持续100 - 200毫秒。这些钙离子瞬变可以：1）促进钙离子内流与细胞内钙离子释放的偶联；2）提供一种调节储存钙离子的机制，而不影响平滑肌的收缩状态；3）在激活细胞中央细胞质中其他钙离子依赖性途径之前或不激活这些途径的情况下，局部激活特定的信号转导途径。后一种可能性表明，细胞内的独立酶促过程可能受同一细胞内第二信使的差异调节。
